Arthroscopic diagnosis of tibiofibular syndesmosis disruption

Value of arthroscopy in the management of acute lesions of the distal tibiofibular joint

PURPOSE

Managing the distal tibiofibular (DTF) joint remains a challenge despite recent developments. Ankle arthroscopy is emerging as a diagnostic and therapeutic means. Our study aimed to compare preoperative imaging data and arthroscopic data, with the hypothesis that imaging alone is insufficient to evaluate acute laxity, and with arthroscopy as the reference examination.

METHODS

All patients treated in 2023 in our department for an acute isolated DTF lesion were included prospectively. Preoperative radiographic and MRI imaging were compared with arthroscopic data.

RESULTS

Ten patients were treated. For five patients, the instability was doubtful after carrying out an appropriate imaging assessment (X-rays of both ankles, MRI). For four of these five patients, instability was confirmed by arthroscopy. Arthroscopy was useful for suturing the anterior bundle of the DTF joint for two patients and allowed for verifying the reduction in the sagittal and coronal planes for two patients. No complications were detected.

CONCLUSIONS

Arthroscopy in isolated acute DTF lesions seems to provide a diagnostic and therapeutic advantage. Its use may allow for exhaustive assessment and complete repair of lesions. It must be offered as soon as possible; a delay in specialized imaging may delay therapeutic care.

Bilateral External Torque CT Reliably Detects Syndesmotic Lesions in an Experimental Cadaveric Study

BACKGROUND

If tibiofibular syndesmotic injury is undetected, chronic instability may lead to persistent pain and osteoarthritis. So far, no reliable diagnostic method has been available. The primary objectives of this study were to determine whether defined lesions of the syndesmosis can be correlated with specific tibiofibular joint displacements caused by external rotational torque and to compare the performance of bilateral external torque computed tomography (BET-CT) and arthroscopy. Secondary objectives included an evaluation of the reliability of CT measurements and the suitability of the healthy contralateral ankle as a reference.

METHODS

Seven pairs of healthy, cadaveric lower legs were tested and assigned to 2 groups: (1) supination-external rotation (SER) and (2) pronation-external rotation (PER). In the intact state and after each surgical step, an ankle arthroscopy and 3 CT scans were performed. During the scans, the specimens were placed in an external torque device with 2.5, 5.0, and 7.5 Nm of torque applied.

RESULTS

The arthroscopic and CT parameters showed significant correlations in all pairwise comparisons. The receiver operating characteristic (ROC) curve analyses yielded the best prediction of syndesmotic instability with the anterior tibiofibular distance on CT, with a sensitivity of 84.1% and a specificity of 95.2% (area under the curve [AUC], 94.8%; 95% confidence interval [CI], 0.916 to 0.979; p < 0.0001) and with the middle tibiofibular distance on arthroscopy, with a sensitivity of 76.2% and specificity of 92.3% (AUC, 91.2%; 95% CI, 0.837 to 0.987; p < 0.0001). Higher torque amounts increased the rate of true-positive results.

CONCLUSIONS

BET-CT reliably detects experimental syndesmotic rotational instability, compared with the healthy side, with greater sensitivity and similar specificity compared with the arthroscopic lateral hook test. Translation of these experimental findings to clinical practice remains to be established.

LEVEL OF EVIDENCE

Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

The Clinical Outcomes of Syndesmotic Flexible Fixation for Syndesmotic Injury With Ankle Fracture

BACKGROUND

We evaluated whether the quality of syndesmotic reduction affects the short-term clinical outcomes of flexible fixation in patients with a rotational ankle fracture.

METHODS

This study included 59 patients (32 men and 27 women) who underwent syndesmotic flexible fixation. The degree of syndesmotic reduction was evaluated on computed tomography (CT) images acquired within 3 days after surgery. We measured the divergence between anterior and posterior incisura at 1 cm above the distal tibial articular joint, then evaluated the degree of fibular rotation relative to the tibia. At 1 year after surgery, an objective clinical evaluation was performed using the American Orthopaedic Foot & Ankle Society (AOFAS) score, the visual analog scale (VAS), and the Foot and Ankle Outcome Score (FAOS). Additionally, repeat arthroscopy was performed during routine implant removal at nearly 1 year postoperatively.

RESULTS

Among 59 patients who underwent syndesmotic flexible fixation, 56 patients had syndesmotic stability on repeat arthroscopy. At 1 year postoperation, AOFAS, VAS, and FAOS scores were, respectively, 90, 2.0, and 94 in the accurate reduction group (n = 24) and 90, 1.0, and 94.5 in the malreduction group (n = 35).

CONCLUSION

Reduction quality after syndesmotic injury with flexible fixation, as determined by early postoperative CT imaging, did not affect patient prognosis. In this cohort, syndesmotic reduction and flexible fixation may produce good clinical outcomes in patients with syndesmotic injury and ankle fracture.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Arthroscopy for Traumatic Ankle Injuries

Using ankle arthroscopy in conjunction to open reduction internal fixation of traumatic ankle injuries can play an important role in the management of these injuries by way of treating intra-articular pathologies, leading to improved patient outcomes. While a majority of these injuries are not treated with concurrent arthroscopy, its addition may lead to more prognostic information to dictate the patient's course. This article has illustrated its use in managing malleolar fractures, syndesmotic injuries, pilon fractures and pediatric ankle fractures. While additional studies may be needed to further support AORIF, it may prove to play a vital role in the future.

Comparison of the diagnostic value of measurements of transverse syndesmotic interval and 'lambda sign' in distinguishing latent syndesmotic diastasis in chronic lateral ankle instability: a cross-sectional study of 188 cases

INTRODUCTION

Chronic lateral ankle instability (CLAI) could accompany with latent syndesmotic diastasis (LSD), which is difficult to distinguish before surgery. Tibiofibular interval width and extravasation of joint fluid ('lambda sign') on MRI are widely used in the diagnosis of syndesmotic injury, but the reliability of these methods in distinguishing the associated LSD in CLAI was rarely studied. Our objective was to compare the diagnostic value of the measurement of the transverse tibiofibular interval and 'lambda sign' on MRI in distinguishing LSD in CLAI and to investigate the radiological predictor that best matched the intraoperatively measured syndesmotic width.

METHODS

138 CLAI patients undergoing arthroscopy in our institute from March 2017 to June 2020 were enrolled (CLAI group). Anterior space width (ASW) and posterior space width (PSW) at 10 mm layer above tibial articular and fluid height above tibial articular surface (FH) were measured on preoperative MRI. The same parameters were measured on MRI of 50 healthy volunteers as control group. At arthroscopy, syndesmotic width was measured and the patients were divided into arthroscopic widening (AW) and arthroscopic normal (AN) subgroup taking 2 mm as critical value. The CLAI group was compared with the control group to explore the interval changes related to CLAI. The AW and AN subgroups were compared to explore the potential diagnostic indicators and reference values for the LSD.

RESULTS

All parameters showed significant difference between CLAI group and control group (p < 0.05), but only PSW (p = 0.004) showed significant difference between AW and AN subgroups other than FH (p = 0.461). Only PSW was involved in formula of multiple-factor analysis (p = 0.005; OR, 1.819; 95%CI, 1.196-2.767). ROC analysis showed critical value of PSW was 3.8 mm (sensitivity, 66%; specificity, 66%; accuracy, 66.7%), while accuracy of lambda sign was 41.3%.

CONCLUSIONS

Transverse tibiofibular interval measurements were more reliable than the 'lambda sign' in distinguishing associated LSD in CLAI patients. The PSW ≥ 3.8 mm could be a predictor of syndesmotic diastasis.

Instabilität des oberen Sprunggelenks

Die symptomatische Bandinstabilität des oberen Sprunggelenks (OSG) ist eine häufige Pathologie und bedarf bei gescheiterter konservativer Therapie oft einer operativen Stabilisierung. Neben Anamnese und subjektiver Wahrnehmung des Patienten liefern klinische Untersuchung, funktionelle Diagnostik, Bildgebung und je nach Bedarf die Arthroskopie des Sprunggelenks wichtige Informationen. Meistens benötigt es eine Kombination mehrerer Untersuchungsmethoden, um die Diagnose einer behandlungsbedürftigen OSG-Instabilität zu stellen. Neben der Beurteilung der Stabilität ist ebenfalls die Feststellung von Zusatzpathologien wichtig. Dies beinhaltet auch das Erkennen einer pathologischen Rückfußachse, was essenziell für die weitere Behandlung sein kann. Die operative Therapie kann mittels Arthroskopie oder offener Operation mit weitgehend erfreulichen klinischen Resultaten durchgeführt werden.

Imaging of Acute Ankle and Foot Sprains

Ankle and foot injuries are very common injuries in the general population, and more so in athletes. MR imaging is the optimal modality to evaluate for ligamentous injuries of the ankle and associated conditions after ankle sprain. In this article, the authors discuss the epidemiology, biomechanics, normal anatomy, and pathology of the ankle as well as injuries of the hindfoot and midfoot that are often associated with ankle injuries.

Augmented stress weightbearing CT for evaluation of subtle tibiofibular syndesmotic injuries in the elite athlete

OBJECTIVE

We aim to present a novel imaging technique utilizing weight-bearing CT with syndesmotic stress to identify subtle, unstable syndesmotic injuries. We illustrate this with a case presentation of such an injury in an elite athlete that ultimately required operative fixation.

MATERIALS AND METHODS

In order to perform an augmented stress weightbearing CT, the patient is in the standing position, feet facing forward, and with weight distributed equally. The patient is then coached to internally rotate the shin and knee. This places an external rotational moment on the TFS due to the planted foot and ankle. The augmented stress images undergo 3D reconstruction and post-processing to render coronal and sagittal images. These are subsequently compared to standard, conventional weightbearing CT images performed without the external rotation stress.

RESULTS

We illustrate this technique by presenting a case in which a 21-year-old collegiate athlete sustained a Grade II syndesmotic injury, diagnosed by MRI and clinical exam without evidence of instability by standard weightbearing CT or weightbearing radiographs. After undergoing the augmented stress weightbearing CT, the instability was noted. This prompted subsequent operative fixation and ultimately return to sport.

CONCLUSION

We propose this technique for diagnosing unrecognized, subtle dynamically unstable syndesmosis injuries where clinical suspicion persists despite negative imaging, particularly in the elite athlete.

Isolated injuries to the lateral ankle ligaments have no direct effect on syndesmotic stability

PURPOSE

This study aim was to detect the impact of lateral ankle ligaments injury on syndesmotic laxity when evaluated arthroscopically in a cadaveric model. The null hypothesis was that lateral ankle ligament injury does not affect the stability of syndesmosis.

METHODS

Sixteen fresh-frozen above-knee amputated cadaveric specimens were divided into two groups of eight specimens that underwent arthroscopic evaluation of the distal tibiofibular joint. In both the groups, the assessment was first done with all syndesmotic and ankle ligaments intact. Thereafter, Group 1 underwent sequential transection of the three lateral ankle ligaments first to identify the effects of lateral ligament injury: (1) anterior talofibular ligament (ATFL), (2) calcaneofibular ligament (CFL), (3) posterior talofibular ligament (PTFL), then followed by the syndesmotic ligaments, (4) AITFL, (5) Interosseous ligament (IOL), and (6) PITFL. Group 2 underwent sequential transection of the (1) AITFL, (2) ATFL, (3) CFL, (4) IOL, (5) PTFL, and (6) PITFL, which represent the most commonly injured pattern in ankle sprain. In all scenarios, four loading conditions were considered under 100 N of direct force: (1) unstressed, (2) a lateral fibular hook test, (3) anterior to posterior (AP) fibular translation test, and (4) posterior to anterior (PA) fibular translation test. Distal tibiofibular coronal plane diastasis at the anterior and posterior third of syndesmosis, as well as AP and PA sagittal plane translation, were arthroscopically measured.

RESULTS

The distal tibiofibular joint remained stable after transection of all lateral ankle ligaments (ATFL, CFL, and PTFL) as well as the AITFL. However, after additional transection of the IOL, the syndesmosis became unstable in both the coronal and sagittal plane. Syndesmosis laxity in the coronal plane was also observed after transection of the ATFL, CFL, AITFL, and IOL. Subsequent transection of the PITFL precipitated syndesmosis laxity in the sagittal plane, as well.

CONCLUSIONS

The findings from the present study suggest that lateral ankle ligament injuries itself do not directly affect the stability of syndesmosis. However, if it combines with IOL injuries, even partial injuries cause syndesmotic laxity. As a clinical relevance, accurate diagnosis is the key for surgeons to determine syndesmosis fixation whether there is only AITFL injury or combined IOL injury in concomitant acute syndesmotic and lateral ligament injury.

Magnetic resonance imaging of ankle ligaments: A pictorial essay

Ankle trauma is commonly encountered and is most often a sprain injury affecting the ligaments. Accurate diagnosis and appropriate treatment rest on knowledge of complex ligamentous anatomy of ankle and the entire spectrum of pathologies. Magnetic resonance imaging (MRI) is the imaging modality of choice for diagnosing ligament pathologies because of its multiplanar capability and high soft tissue contrast. With MRI, it is possible to triage and attribute the cause of post traumatic ankle pain to bone, ligament, or tendon pathologies, which otherwise overlap clinically. In this pictorial essay, emphasis is given to the intricate and unique anatomy and orientation of ankle ligaments. Pathologies of ankle ligaments have been elaborated.

Arthroscopic characterization of syndesmotic instability in the coronal plane: Exactly what measurement matters?

BACKGROUND

Although ankle arthroscopy is increasingly used to diagnose syndesmotic instability, precisely where in the incisura one should measure potential changes in tibiofibular space or how much tibiofibular space is indicative of instability, however, remains unclear. The purpose of this study was to determine where within the incisura one should assess coronal plane syndesmotic instability and what degree of tibiofibular space correlates with instability in purely ligamentous syndesmotic injuries under condition of lateral hook stress test (LHT) assessment.

METHODS

Ankle arthroscopy was performed on 22 cadaveric specimens, first with intact ankle ligaments and then after sequential sectioning of the syndesmotic and deltoid ligaments. At each step, a 100N lateral hook test was applied through a lateral incision 5 cm proximal to the ankle joint and the coronal plane tibiofibular space in the stressed and unstressed states were measured at both anterior and posterior third of the distal tibiofibular joint, using calibrated probes ranging from 0.1 to 6.0 mm, in 0.1 mm of increments. The anterior and posterior points of measurements were defined as the junction between the anterior and middle third, and junction between posterior and middle third of the incisura, respectively.

RESULTS

Anterior third tibiofibular space measurements did not correlate significantly with the degree of syndesmotic instability after transection of the ligaments, neither before nor after applying LHT at all the three groups of different sequences of ligament transection (P range 0.085-0.237). In contrast, posterior third tibiofibular space measurements correlated significantly with the degree of syndesmotic instability after transection of the ligaments, both with and without applying stress in all the groups of different ligament transection (P range <0.001-0.015). Stressed tibiofibular space measurements of the posterior third showed higher sensitivity and specificity when compared to the stressed anterior third measurements. Using 2.7 mm as a cut off for posterior third stressed measurements has both sensitivity and specificity about 70 %.

CONCLUSION

Syndesmotic ligament injury results in coronal plane instability of the distal tibiofibular articulation that is readily identified arthroscopically with LHT when measured in the posterior third of the incisura.

CLINICAL RELEVANCE

When applying LHT, tibiofibular space measurement for coronal plane instability along the anterior third of the incisura is less sensitive for identifying syndesmotic instability and may miss this diagnosis especially when subtle.

Tibiofibular Space Widening Assessment With a Ball-Tipped Probe in a Syndesmosis Injury Model

Assessment of syndesmotic instability is not precise with existing evaluation methods. This study was conducted to investigate the use of a ball-tipped probe under arthroscopy for quantitative assessment of tibiofibular space widening in a syndesmosis injury model. The test specimens were 5 uninjured ankles from Thiel-fixed cadavers of 2 male subjects and 3 female subjects of mean age of 82.4 years at death. The ball-tipped probe consisted of a metal probe having a ball at each end with diameters ranging from of 1.5 mm to 5.0 mm, in increments of 0.5 mm. The tibiofibular joint was observed arthroscopically as the largest-diameter ball probe as possible was inserted into its anterior third, middle, or posterior third portion with the ankle in natural plantarflexion or under external rotational stress. These measurements were performed for the uninjured ankle and then performed following Bassett's ligament sectioning, anterior inferior tibiofibular ligament sectioning, interosseous membrane distal 15 cm sectioning, or deltoid ligament, and posterior inferior tibiofibular ligament sectioning, with the sections added in this sequence and each followed by a similar assessment. The results of quantitative assessment of tibiofibular space widening with the ball-tipped probe in the syndesmosis injury model under arthroscopy were that the maximum possible diameter of ball probe that could be inserted was 1.5 to 2.0 mm in the uninjured state, 3.0 to 3.5 mm in the sectioned anterior inferior tibiofibular ligament model, and 5.0 mm in the severe-state model. The ball probe can serve as an effective tool for quantitative assessment of the intraoperative instability in cases of syndesmosis injury.

Diagnosis of tibiofibular syndesmosis instability in Weber type B malleolar fractures

Objective

This study was performed to analyze the clinical value of X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) examinations for the diagnosis of distal tibiofibular syndesmosis injuries in Weber type B ankle fractures with reference to the ankle arthroscopic findings.

Methods

This retrospective clinical study involved 52 patients with type B ankle fractures from August 2014 to January 2018. We analyzed the patients’ preoperative imaging data and judged the stability of the distal tibiofibular syndesmosis using X-ray, CT, and MRI examinations. We also evaluated the syndesmosis stability with arthroscopy both statically and dynamically.

Results

With the arthroscopic findings as the standard, the sensitivity of X-ray for diagnosing syndesmosis instability was 52.8%, the specificity was 100%, and the diagnostic efficiency was 67.3%. The sensitivity of CT for diagnosing syndesmosis instability was 77.8%, the specificity was 100%, and the diagnostic efficiency was 84.6%. The sensitivity of MRI for diagnosing syndesmosis instability was 100%, the specificity was 81.3%, and the diagnostic efficiency was 94.2%.

Conclusion

This study suggests that an arthroscopic examination may be recommended when the X-ray or CT features are different from the MRI findings while diagnosing tibiofibular syndesmosis instability in Weber type B malleolar fractures.

Identifying Intra-Articular Pathology With Arthroscopy Prior to Open Ankle Fracture Fixation

Purpose

To assess the prevalence of intra-articular findings with ankle arthroscopy in patients undergoing operative fixation for ankle fractures.

Methods

This is a retrospective review of ankle fractures that were treated with arthroscopy and open reduction and internal fixation by a single surgeon. Between August 2016 and July 2018, operative reports, office notes, and images were reviewed to identify intra-articular pathology and fracture type. An analysis was performed with regard to fracture type, presence and location of osteochondral lesions, loose-bodies, syndesmotic injury, and deltoid injury.

Results

Fifty-seven ankle fractures were identified that met inclusion criteria. In total, 84.2% of the fractures had intra-articular pathology, most commonly a syndesmotic injury followed by presence of intra-articular loose bodies and osteochondral defects.

Conclusions

In our study, use of arthroscopy before open ankle fracture fixation identified intra-articular pathology in 84.2% of subjects. The most common pathology was syndesmotic injury. The addition of an arthroscopic assessment in patients with operatively treated ankle fractures may help improve treatment provided to patients during ankle fracture surgery.

Level of Evidence

Level 4 Therapeutic Case Series.

Diagnosing syndesmotic instability with dynamic ultrasound - establishing the natural variations in normal motion

BACKGROUND

Syndesmotic instability, when subtle, is challenging to diagnose and often requires visualization of the syndesmosis during applied stress. The primary aim was to assess normal distal tibiofibular motion in the sagittal plane using dynamic ultrasound under stress conditions. The secondary aim was to evaluate the reliability of dynamic stress ultrasonography.

METHODS

Twenty-eight participants without history of ankle injury were included. Sagittal fibular translation was generated by applying a manual force to the fibula from anterior to posterior and from posterior to anterior. Distance between the ultrasound probe and the fibula was taken at two predefined points: 1) no force applied and, 2) during maximum force application. Each participant was scanned twice by two independent examiners, and each scan was analysed by two independent examiners. Three participants were scanned a second time by the same examiner who analysed these films twice to assess for intraobserver agreement. Means of exam 1 versus exam 2 were compared using a mixed linear model. Agreement among observers was calculated using intraclass correlation coefficients (ICC) interpreted as 0.4, poor; 0.4 〈 ICC < 0.59, acceptable; 0.6 < ICC < 0.74, good; ICC 〉 0.74, excellent.

RESULTS

Fifty-six ankles were included in the study, including 16 (57%) males and 12 (42%) females. Average anterior to posterior fibular sagittal translation was 0.89 ± 0.6 mm and posterior to anterior fibular sagittal translation was 0.49 ± 1.1 mm. Anterior to posterior translation means of exam 1 versus exam 2 showed no significant differences, means of 0.81 mm [0.7-0.9] versus 0.77 mm [0.7-1.0], and posterior to anterior means [95% CI] of 0.42 mm [0.3-0.5] versus 0.44 mm [0.2-0.6] (p-values 0.416 and 0.758, respectively). Excellent Inter- and intraobserver agreement was found for all measurements taken.

CONCLUSION

Dynamic ultrasound allows one to effectively and readily evaluate sagittal translation of the distal tibiofibular joint. It is able to afford bilateral comparisons, which becomes critical as the amount of syndesmotic instability approaches greater degrees of subtlety.

Direct visualization of the syndesmosis for evaluation of syndesmotic disruption: A cadaveric study

Objectives:

Radiologic criteria for syndesmosis instability evaluation remain controversial and direct visualization (DV) of the distal tibiofibular articulation is an alternative diagnostic method worthy of further investigation. We speculate that DV is a more accurate way to evaluate syndesmosis instability than fluoroscopy. The purpose of this study is to determine whether syndesmosis instability can accurately be recognized through DV and if this new intraoperative diagnostic method is more sensitive than fluoroscopy in detecting syndesmosis instability.

Methods:

Ten cadaveric ankles were tested using a sequential iatrogenic syndesmosis injury model. Specimens were tested incrementally with the lateral stress test (LST) and the external rotation stress test (ERT). The resulting instability was measured directly and fluoroscopically with a true mortise view by using medial clear space (MCS) and tibiofibular clear space (TFCS).

Results:

DV detected a 2-ligaments injury at a mean diastasis of 3.02 mm (P = 0.0077) and 3.19 mm (P = 0.0077) with the LST and ERT, respectively. Fluoroscopically, TFCS showed a significant diastasis only with a complete syndesmosis rupture while MCS did not show any significant differences.

Conclusions:

DV of the syndesmosis in a cadaver injury model appears to be more sensitive than fluoroscopy in identifying injury, especially incomplete syndesmotic disruption.

Evaluating success rate and comparing complications of operative techniques used to treat chronic syndesmosis injuries

Purpose

To assess the success rate and complications of the surgical interventions used to manage chronic syndesmosis injuries.

Methods

Multiple online databases were queried to identify studies reporting operative intervention for chronic syndesmosis injuries.

Results

Modalities of operative fixation include suture-button fixation, arthroscopy and debridement, as well as arthrodesis. The use of operative treatment is effective; however, more direct comparison studies are necessary to evaluate the efficacy of each treatment.

Conclusion

Various operative procedures have been used for the management of chronic syndesmotic injuries but further prospective studies are necessary to determine the type of treatment that should be indicated.

Ankle stability in ankle fracture

Restoration of normal ankle kinematics should be the all-encompassing ethos in the approach to management of ankle fractures. To do this, the ligamentous stabilisers must also form part of its assessment and definitive management and be considered during index fracture fixation surgery. This article is a review of the anatomy, mechanics and clinical testing of instability in ankle fractures.

A step-by-step arthroscopic examination of the anterior ankle compartment

PURPOSE

Despite the increased use of ankle dorsiflexion without distraction, no reports have specifically addressed the arthroscopic anatomy of the ankle in this position. The purpose of this study was to describe the normal arthroscopic anatomy of the ankle joint, when using the ankle dorsiflexion and the dynamic distraction technique, and to propose an arthroscopic examination system for the anterior ankle compartment.

METHODS

Ankle arthroscopy was performed in 20 fresh frozen specimens. Arthroscopic examination was performed with the arthroscope introduced through the anteromedial portal. The anterior compartment was examined in ankle dorsiflexion without distraction. The compartment was examined in four steps: (1) lateral area including the lateral gutter; (2) the central area of the anterior tibial rim; (3) the medial area including the medial gutter; (4) the talar neck. Next, distraction was applied to visualise the anterior compartment again and to examine the central and posterior ankle compartments.

RESULTS

Anatomic intra-articular structures were visualised in all specimens. Four intra-articular fat pads, one anteromedial, two syndesmotic and another posteromedial, were constantly observed. A description of the normal arthroscopic anatomy of the ankle using the ankle dorsiflexion and the dynamic distraction technique is detailed for the anterior, central and posterior compartments.

CONCLUSION

The ankle arthroscopic procedure without distraction allows constant visualisation of the ATFL's superior fascicle on the floor of the lateral gutter, the ATiFL's distal fascicle laterally and the most anterior margin of the deltoid ligament in the medial gutter (anterior tibiotalar ligament). However, ankle distraction is required to observe the central and posterior compartments, but it does not provide optimal visualisation of the anterior ankle compartment structures.

LEVEL OF EVIDENCE

V.

MRI of the distal tibiofibular joint

The distal tibiofibular joint is a fibrous joint that plays a crucial role in the stability of the ankle joint. It is stabilized by three main ligaments: the anterior inferior tibiofibular ligament, the posterior inferior tibiofibular ligament, and the interosseous tibiofibular ligament, which are well delineated on magnetic resonance imaging. Pathology of the distal tibiofibular joint is mostly related to trauma and the longer-term complications of trauma, such as soft tissue impingement, heterotopic ossification, and synostosis. This review article outlines the MRI anatomy and pathology of this joint.

The arthroscopic syndesmotic assessment tool can differentiate between stable and unstable ankle syndesmoses

PURPOSE

Patients with stable isolated injuries of the ankle syndesmosis can be treated conservatively, while unstable injuries require surgical stabilisation. Although evaluating syndesmotic injuries using ankle arthroscopy is becoming more popular, differentiating between stable and unstable syndesmoses remains a topic of on-going debate in the current literature. The purpose of this study was to quantify the degree of displacement of the ankle syndesmosis using arthroscopic measurements. The hypothesis was that ankle arthroscopy by measuring multiplanar fibular motion can determine syndesmotic instability.

METHODS

Arthroscopic assessment of the ankle syndesmosis was performed on 22 fresh above knee cadaveric specimens, first with all syndesmotic and ankle ligaments intact and subsequently with sequential sectioning of the anterior inferior tibiofibular ligament, the interosseous ligament, the posterior inferior tibiofibular ligament, and deltoid ligaments. In all scenarios, four loading conditions were considered under 100N of direct force: (1) unstressed, (2) a lateral hook test, (3) anterior to posterior (AP) translation test, and (4) posterior to anterior (PA) translation test. Anterior and posterior coronal plane tibiofibular translation, as well as AP and PA sagittal plane translation, were arthroscopically measured.

RESULTS

As additional ligaments of the syndesmosis were transected, all arthroscopic multiplanar translation measurements increased (p values ranging from p < 0.001 to p = 0.007). The following equation of multiplanar fibular motion relative to the tibia measured in millimeters: 0.76*AP sagittal translation + 0.82*PA sagittal translation + 1.17*anterior third coronal plane translation-0.20*posterior third coronal plane translation, referred to as the Arthroscopic Syndesmotic Assessment tool, was generated from our data. According to our results, an Arthroscopic Syndesmotic Assessment value equal or greater than 3.1 mm indicated an unstable syndesmosis.

CONCLUSIONS

This tool provides a more reliable opportunity in determining the presence of syndesmotic instability and can help providers decide whether syndesmosis injuries should be treated conservatively or operatively stabilized. The long-term usefulness of the tool will rest on whether an unstable syndesmosis correlates with acute or chronic clinical symptoms.

Diagnostic capability of dynamic ultrasound evaluation of supination-external rotation ankle injuries: a cadaveric study

BACKGROUND

Ankle syndesmosis injuries are common and range in severity from subclinical to grossly unstable. Definitive diagnosis of these injuries can be made with plain film radiographs, but are often missed when severity or image quality is low. Computed tomography (CT) and magnetic resonance imaging (MRI) can provide definitive diagnosis, but are costly and introduce the patient to radiation when CT is used. Ultrasonography may circumvent many of these disadvantages by being inexpensive, efficient, and able to detect injuries without radiation exposure. The purpose of this study was to evaluate the ability of ultrasonography to detect early stage supination-external rotation (SER) ankle syndesmosis injuries with a dynamic external rotational stress test.

METHODS

Nine, all male, fresh frozen specimens were secured to an ankle rig and stress tested to 10 Nm of external rotational torque with ultrasonography at the tibiofibular clear space. The ankles were subjected to syndesmosis ligament sectioning and repeat stress measurements of the tibiofibular clear space at peak torque. Stress tests and measurements were repeated three times and averaged and analyzed using a repeated one-way analysis of variance (ANOVA). There were six ankle injury states examined including: Intact State, 75% of AITFL Cut, 100% of AITFL Cut, Fibula FX - Cut 8 cm proximal, 75% PITFL Cut, and 100% PITFL Cut.

RESULTS

Dynamic external rotation stress evaluation using ultrasonography was able to detect a significant difference between the uninjured ankle with a tibiofibular clear space of 4.5 mm and the stage 1 complete injured ankle with a clear space of 6.0 mm (P < .02). Additionally, this method was able to detect significant differences between the uninjured ankle and the stage 2-4 injury states.

CONCLUSION

Dynamic external rotational stress evaluation using ultrasonography was able to detect stage 1 Lauge-Hansen SER injuries with statistical significance and corroborates criteria for diagnosing a syndesmosis injury at ≥6.0 mm of tibiofibular clear space widening.

Syndesmotic Ligaments of the Ankle: Anatomy, Multimodality Imaging, and Patterns of Injury

Injuries to the syndesmotic ligaments of the ankle or "high ankle sprains" are common in acute ankle trauma but can be difficult to diagnose both clinically and on imaging. Missed injuries to the syndesmosis can lead to chronic ankle instability, which can cause persistent pain and lead to early osteoarthritis. This review will illustrate the anatomy of the syndesmotic ligamentous complex, describe radiographic, CT, and MR imaging of the syndesmosis, demonstrate typical mechanisms of injuries and associated fracture patterns, and provide an overview of important management considerations.

MRI for high ankle sprains with an unstable syndesmosis: posterior malleolus bone oedema is common and time to scan matters

PURPOSE

Early clinical examination combined with MRI allows accurate diagnosis of syndesmosis instability after a high ankle sprain. However, patients often present late. The aims of the current study were to describe MRI characteristics associated with syndesmosis instability and to test the hypothesis that MRI patterns would differ according to time from injury.

METHODS

Over a 5-year period, 164 consecutive patients who had arthroscopically proven syndesmosis instability requiring fixation were retrospectively studied. Patients with distal fibula fractures were not included. Injuries were classified as acute in 108 patients (< 6 weeks), intermediate in 32 (6-12 weeks) and chronic in 24 patients (> 12 weeks).

RESULTS

Posterior malleolus bone oedema was noted in 65 (60.2%), and posterior malleolus fracture in 17 (15.7%) of acute patients, respectively, which did not significantly differ over time. According to MRI, reported rates of posterior syndesmosis disruption significantly differed over time, observed in 101 (93.5%), 28 (87.5%) and 13 (54.2%) of acute, intermediate and chronic patients, respectively (p < 0.001). Apparent rates of PITFL injury significantly reduced with time (p < 0.001).

CONCLUSIONS

MRI detected a posterior syndesmosis injury in 93.5% of patients acutely but became less reliable with time. The clinical relevance of this study is that posterior malleolus bone oedema may be the only marker of a complete syndesmosis injury and can help clinically identify those injuries which require arthroscopic assessment for instability. If suspicious of a high ankle sprain, we advocate early MRI assessment to help determine stable versus unstable injuries as MRI becomes less reliable after 12 weeks.

LEVEL OF EVIDENCE

III.

Reducing the Syndesmosis Under Direct Vision: Where Should I Look?

OBJECTIVES

To compare the quality of syndesmotic reduction obtained using the incisura versus the ankle articular surface as the visual cue. Secondarily, we evaluated the difference in the anterior to posterior depth of the fibula to the tibia at the joint level and the fibula to the incisura 1 cm above the joint.

METHODS

Seven surgeons reduced disrupted syndesmoses of 10 cadaveric ankles using either the anterolateral articular surface of the distal tibia to the anteromedial fibular articular surface or the location of the fibula within the incisura as a visual reference. Malreductions in translation were measured in millimeter from the anatomical position of the fibula. The anterior to posterior distances of the tibia and fibula were also measured at both levels to determine the differences in their depths.

RESULTS

The translational reduction was within 2 mm in 93% (0.7 ± 0.7 mm) of reductions using the articular surface as a reference compared with 80% (1.2 ± 1.0 mm) using the incisura as a reference (P = 0.0001). All surgeons' reductions were better using the joint articular surface as the visual reference. The difference in the fibular and the tibial depth was smaller at the level of the articular surface versus the incisura (2.1 mm vs. 5.9 mm; P = 0.0002).

CONCLUSIONS

The articular surface is a significantly more accurate visual landmark for translational reduction of the syndesmosis. This is potentially explained by the larger differences in the fibula and tibial depth at the incisura versus the articular surface.

Arthroscopic Reduction and Minimally Invasive Surgery in Supination-External Rotation Ankle Fractures: A Comparative Study With Open Reduction

PURPOSE

To describe an algorithm for arthroscopic reduction and minimally invasive surgery (ARMIS) and compare the surgical outcomes with standard open reduction-internal fixation (ORIF) for the treatment of supination-external rotation (SER) ankle fractures.

METHODS

The inclusion criteria for this study were patients aged 16 years or older, the presence of a unilateral SER fracture, and injuries less than 2 weeks old. We retrospectively identified patients with SER fractures who underwent ORIF from January 2008 to December 2011 or ARMIS from January 2012 to December 2015. Data collected in December 2013 for the ORIF group and in December 2017 for the ARMIS group were compared. The algorithm for ARMIS was minimally invasive plating for lateral malleolar fractures first, followed by ankle arthroscopy for detection of syndesmotic injuries and then arthroscopic reduction of medial malleolar fractures or mini-open repair of the deltoid ligament. The talocrural angle, fibular length, tibiomedial malleolar angle, medial clear space, and tibiofibular clear space were measured radiographically. Functional evaluations included the visual analog scale pain score, American Orthopaedic Foot & Ankle Society ankle-hindfoot scales, and range of motion of bilateral ankles. Complications and reoperations were recorded for comparison.

RESULTS

A total of 105 patients with SER fractures, 65 in the ARMIS group and 40 in the ORIF group, were included. Significantly lower incidences of complications (7.7% vs 27.5%, P = .006) and reoperations (1.5% vs 12.5%, P = .029) were found in the ARMIS group than in the ORIF group. More syndesmotic injuries were detected in the ARMIS group than in the ORIS group (80% vs 57.5%, P = .021). The visual analog scale pain score was significantly lower on day 3 postoperatively in the ARMIS group than in the ORIS group (1.96 ± 1.18 vs 2.83 ± 1.07, P = .027). The postoperative stay was shorter in the ARMIS group than in the ORIF group (3.66 ± 1.39 days vs 4.46 ± 2.23 days, P = .024). The operative time was longer in the ARMIS group than in the ORIS group (105.22 ± 27.13 minutes vs 93.59 ± 22.79 minutes, P = .038). A longer fluoroscopic time (0.43 ± 0.25 minutes vs 0.17 ± 0.07 minutes, P < .001) and a higher dose of irradiation (1,216.46 ± 603.99 μGy vs 389.38 ± 217.89 μGy, P < .001) were observed in the ARMIS group. No significant differences in radiographic measurements were found between the operative and nonoperative ankles in both groups.

CONCLUSIONS

Our algorithm and the ARMIS techniques may be a safe, reliable, and effective option in the treatment of SER fractures. ARMIS achieves promising surgical outcomes with less early postoperative pain, a shorter postoperative stay, and lower incidences of complications and reoperations compared with ORIF. However, the operative time is longer and the irradiation dose is higher with the ARMIS techniques.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Diagnostic Accuracy of Radiologic Methods for Ankle Syndesmosis Injury: A Systematic Review and Meta-Analysis

: Misdiagnosis and inadequate treatment of syndesmosis could result in significant long-term morbidity including pain, instability, and degenerative changes of the ankle joint. The objective of this systematic review and meta-analysis was to determine whether radiologic tests accurately and reliably diagnose ankle syndesmosis injury. Medline, Embase, and Cochrane were searched. The database search resulted in 258 full text articles that we assessed for eligibility, we used eight studies that met all the inclusion criteria. In subgroup meta-analysis, the sensitivity analysis showed significant differences only in the MRI (Magnetic Resonance Imaging), and specificity was not statistically significant. In diagnostic meta-analysis, the pooled sensitivity and specificity were 0.528 and 0.984 for X-rays, 0.669 and 0.87&nbsp;for CT (Computed Tomography), and 0.929 and 0.865 for MRI, all respectively. For sensitivity, MRI showed significantly sensitivity as higher than the other methods, and we detected no significance for specificity. Syndesmosis injuries differed significantly in the accuracy of radiological methods according to the presence of accompanied ankle fractures. In patients with fractures, simple radiography has good specificity, and CT and MRI have high sensitivity and specificity irrespective of fracture; in particular, MRI has similar accuracy to gold standard arthroscopic findings.

Functional Outcome of Pronation-External Rotation-Weber C Ankle Fractures with Supracollicular Medial Malleolar Fracture Treated with or without Syndesmotic Screws: A Retrospective Comparative Cohort Study

Background:

In treatment of ankle fracture, intraoperative stress tests are used to assess the syndesmotic injury and instability. However, the optimized timing of the strees test should be applied whether in pre- or post-bony fixation during operation is seldom be reported in previous studies. The different strategies on stress test timing would exhibit opposite results within a type of pronation-external rotation (PER) fractures with supracollicular medial malleolar (SMM) fractures. This study was designed to assess the 3-year functional outcomes of the special PER fractures with or without a syndesmotic transfixation based on the results of two different intraoperative stress test strategies.

Methods:

This retrospective cohort study included 61 PER injury-Weber C ankle fractures combined with SMM fractures who were treated in Beijing Jishuitan Hospital between 2013 and 2014 and followed up for 3 years. Stress test was performed twice intraoperatively. A positive intraoperative stress test before bony fixation and a negative intraoperative stress test after bony fixation were found in these included patients. Twenty-nine patients (Group 1) were treated without a supplemental syndesmotic screw fixation, according to the negative intraoperative stress test after bony fixation, while 32 patients (Group 2) were treated with an additional syndesmotic screw fixation based on the positive intraoperative stress test before bony fixation. The American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale and Visual Analog Scale (VAS) for pain scores were the main measurements of outcome. The statistical index of demographic data, fracture morphologic data, time interval of follow-up, AOFAS and VAS were recorded and assessed by SPSS 21.0 software through Fisher exact tests and one-way analysis of variance. The associations between the main outcomes and influential factors were evaluated by linear regression models.

Results:

We observed no difference in the distribution of age, sex, presence of associated posterior malleolus (PM), fracture dislocation, and fixation of associated PM between two treatment groups. With the numbers available, no statistically significant association could be detected with regard to the AOFAS (Group 1 vs. Group 2, 96.72 ± 6.20 vs. 94.63 ± 8.26, F = 1.24, P = 0.27) and VAS (Group 1 vs. Group 2, 1.47 ± 2.14 vs. 0.72 ± 1.49, F = 2.44, P = 0.12) in association with two strategies.

Conclusions:

The present study indicates no difference to the use of the syndesmotic screw in terms of the functional outcome between syndesmosis transfixation and no-fixation patients among PER-Weber C ankle fracture patients with SMM fracture after 3-year follow-up. More attention should be paid to pre- and post-bony-fixation intraoperative stress tests and the morphology of medial malleoli fractures in ankle fractures.

Arthroscopic Grading of Injuries of the Inferior Tibiofibular Syndesmosis

The objective of this study was to describe the technical details of performing a newly developed arthroscopic grading of inferior tibiofibular syndesmosis injuries. Arthroscopy is emerging as the gold standard for evaluating painful, unstable ankles. The inferior tibiofibular syndesmosis contributes substantially to disorders of the ankle. However, no structured grading system exists that would help surgeons evaluate injuries of the syndesmosis. Seventy-eight patients with pain or instability symptoms in the ankle were arthroscopically evaluated for syndesmosis injury. The lesions were graded according to the prospectively developed protocol. More than 61% of the patients had syndesmosis disruptions of various grades affecting the anterior/posterior ligaments or both ligaments. Fourteen patients had anterior ligament disruptions whereas 4 patients had posterior lesions; another 7 patients had both ligaments asymmetrically injured. Eighteen of the 78 patients had symmetric grade 1 lesions, and 5 had grade 2 lesions. More than half of chronic ankle pain cases have syndesmotic lesions. Symmetrical lesions of the anterior and posterior ligaments predominate, followed by isolated anterior ligament disruptions. The proposed grading system for inferior tibiofibular syndesmosis disruptions serves as a guide to systematic documentation of injuries of the syndesmosis.

Assessing Quality of Syndesmotic Reduction in Surgically Treated Acute Syndesmotic Injuries: A Systematic Review

There is no universal method with cutoff values for the assessment of distal tibiofibular joint reduction in acute syndesmotic injuries. It is important to detect malreductions because they may lead to impaired functional outcome and may demand reoperations. The aim of this study was to systematically review the literature to evaluate the appropriateness of different image techniques in determining syndesmotic malalignment. A literature search was conducted in Medline, Embase, and the Cochrane Library to search for articles assessing syndesmotic reduction. Excluded were articles where no criteria and/or measurements for syndesmotic reduction were provided, only normative values were provided and reviews. In total, 2157 articles were found, of which 1421 studies were screened for title and abstract after exclusion of duplicates. One hundred ten studies were eligible for full-text analysis. Of these, 61 were excluded. Three studies where added after screening the included references. Fifty-two studies were included, of which 32 were original publications and 20 were publications referring to the original publications. From the original publications, 14 used plains radiographs, 19 computed tomographic (CT) scans, and 5 used 3-dimensional CT scans (some authors used >1 modality in their study). For each modality, a large number of parameters and different cutoff values were reported. CT scanning is superior to plain radiography in the assessment of the quality of joint reduction. Parameters used the most were fibular position in the incisura and fibular rotation. The criteria for adequate reduction should at least include the position of the fibula in the incisura and rotation of the fibula, while ensuring adequate fibular length, all equaling or at least approaching the values of the uninjured contralateral side.

Postoperative Reoperations and Complications in 32,307 Ankle Fractures With and Without Concurrent Ankle Arthroscopic Procedures in a 5-Year Period Based on a Large U.S. Healthcare Database

Residual symptoms often persist even after successful operative reduction and internal fixation (ORIF) of ankle fractures. Concurrent ankle arthroscopic procedures (CAAPs) have been proposed to improve clinical outcomes; however, a dearth of evidence is available supporting this practice. The purpose of the present study was to investigate the reoperation and complication rates after ORIF of ankle fractures with and without CAAPs. Reoperations and complications after ORIF of ankle fractures were identified using the PearlDiver database from January 2007 to December 2011. The CAAPs included bone marrow stimulation, debridement, synovectomy, and unspecified cartilage procedures. Reoperation procedures consisted of ankle fracture repeat fixation, arthroscopic procedures, osteochondral autograft transfers, and ankle arthrodesis. Of the 32,307 patients who underwent ankle fracture fixation, 248 received CAAP and 32,059 did not. No significant difference was found in the reoperation rate between the 2 groups (7.7% versus 8.6%; odds ratio 0.89; 95% confidence interval 0.55 to 1.42; p = .61). Of the 248 patients in the CAAP group, 19 (7.7%) underwent reoperation, of which 13 (68.4%) were arthroscopic debridement and 6 were either ankle refixation or osteochondral autograft transfer. For the non-CAAP group, 3021 reoperation procedures were performed, consisting of ankle refixation in 83.2%, arthroscopic procedures in 14.3%, and ankle arthrodesis in 2.5%. The complication rate in the non-CAAP group included wound dehiscence in 2.4%, wound surgery in 0.4%, deep vein thrombosis in 0.8%, and pulmonary embolism in 0.4%. No complications were detected in the CAAP group. Ankle fracture fixation with CAAPs did not increase the postoperative reoperation rate compared with ankle fracture fixation without CAAPs.

Imaging in Foot and Ankle Instability

This article reviews the imaging aspects relevant to ligamentous instabilities of the foot and ankle with a focus on MRI and ultrasound imaging. A pictorial review of the anatomy of the medial and lateral ankle ligaments, syndesmosis, spring ligament, Lisfranc complex, hallux sesamoid complex, and lesser toe plantar plate as seen on MRI is presented. Selected cases of ligamentous pathology relevant to foot and ankle instability are presented. The value of imaging in the assessment of foot and ankle instability is reviewed.

Ankle Arthroscopic Surgery

Ankle arthroscopy is a diagnostic and therapeutic surgical procedure which was first attempted on cadavers by Dr Burman in 1931 and first successfully described in patients by Dr Takagi in 1939. Two general approaches to ankle arthroscopy currently exist: (1) anterior ankle arthroscopy and (2) posterior ankle arthroscopy. The indications for ankle arthroscopy have expanded as increased experience has been obtained treating various pathologic entities and as the surgical results have been reported in the literature. There has been significant progress in ankle arthroscopic surgery over the past decades, notably allowing surgical procedures to be performed with fewer complications and with quicker return to work and play. We anticipate that expanding indications for arthroscopic ankle surgical procedures combined with further development of biomedical devices to enhance these procedures will result in improved patient outcomes in the future.

Imaging in syndesmotic injury: a systematic literature review

OBJECTIVES

To give a systematic overview of current diagnostic imaging options for assessment of the distal tibio-fibular syndesmosis.

MATERIALS AND METHODS

A systematic literature search across the following sources was performed: PubMed, ScienceDirect, Google Scholar, and SpringerLink. Forty-two articles were included and subdivided into three groups: group one consists of studies using conventional radiographs (22 articles), group two includes studies using computed tomography (CT) scans (15 articles), and group three comprises studies using magnet resonance imaging (MRI, 9 articles).The following data were extracted: imaging modality, measurement method, number of participants and ankles included, average age of participants, sensitivity, specificity, and accuracy of the measurement technique. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool was used to assess the methodological quality.

RESULTS

The three most common techniques used for assessment of the syndesmosis in conventional radiographs are the tibio-fibular clear space (TFCS), the tibio-fibular overlap (TFO), and the medial clear space (MCS). Regarding CT scans, the tibio-fibular width (axial images) was most commonly used. Most of the MRI studies used direct assessment of syndesmotic integrity. Overall, the included studies show low probability of bias and are applicable in daily practice.

CONCLUSIONS

Conventional radiographs cannot predict syndesmotic injuries reliably. CT scans outperform plain radiographs in detecting syndesmotic mal-reduction. Additionally, the syndesmotic interval can be assessed in greater detail by CT. MRI measurements achieve a sensitivity and specificity of nearly 100%; however, correlating MRI findings with patients' complaints is difficult, and utility with subtle syndesmotic instability needs further investigation. Overall, the methodological quality of these studies was satisfactory.

Role of the Deltoid Ligament in Syndesmotic Instability

BACKGROUND

The deltoid ligament (DL) is the principal ligamentous stabilizer of the medial ankle joint. Little is known, however, about the contribution of the DL toward stabilizing the syndesmosis. The aim of this study was to arthroscopically evaluate whether the DL contributes to syndesmotic stability in the coronal plane.

METHODS

Eight above-knee cadaveric specimens were used in this study. A lateral hook test was performed by applying 100 N of lateral force to the fibula in the intact state and after sequential transection of the DL, anterior-inferior tibiofibular ligament (AITFL), interosseous ligament (IOL), and posterior-inferior tibiofibular ligament (PITFL). At each stage, distal tibiofibular diastasis was measured arthroscopically at both the anterior and posterior third of the incisura and compared to stress measurements of the intact syndesmosis. Measurements were performed using probes ranging from 0.1 to 6.0 mm, with 0.1-mm increments.

RESULTS

There was no significant increase in diastasis at either the anterior or posterior third of the tibiofibular articulation after isolated DL disruption, nor when combined with AITFL transection. In contrast, a significant increase in diastasis was observed following additional disruption of the IOL (anterior and posterior third diastasis, P= .012 and .026, respectively), and after transection of all 3 syndesmotic ligaments (anterior and posterior third diastasis, P=.001 and .001, respectively).

CONCLUSION

When evaluating the syndesmosis arthroscopically in a cadaveric model under lateral stress, neither isolated disruption of the DL nor combined DL and AITFL injuries destabilized the syndesmosis in the coronal plane. In contrast, the syndesmosis became unstable if the DL was injured in conjunction with partial syndesmotic disruption that included the AITFL and IOL.

CLINICAL RELEVANCE

Disruption of the DL appeared to destabilize the syndesmosis in the coronal plane when associated with partial disruption of the syndesmosis (AITFL and IOL).

A Radiographic Dye Method for Intraoperative Evaluation of Syndesmotic Injuries

BACKGROUND

The Chertsey test has been recently defined as an intraoperative test for the detection of the syndesmotic injuries by the application of intra-articular contrast. However, no study has investigated the reliability and comparative analysis of the Chertsey test. The purpose of this study was to explore the diagnostic accuracy of the Chertsey test in predicting syndesmosis instability of the injured ankle, with correlation to preoperative computed tomography (CT) findings.

METHODS

A total of 39 patients who were operated on due to the unilateral ankle fracture and had no complaint on the contralateral ankle joint were included in the study. An intraoperative Chertsey test was performed on all ankle fractures and bilateral ankle CT was obtained preoperatively. Ankles were classified as Chertsey +, Chertsey -, and contralateral control group. The morphology categorization, width, and volume of the syndesmotic region were measured on axial images of the CT. Mann-Whitney U test was used to compare the data. Intraobserver and interobserver agreements were accessed by calculating the intraclass correlation coefficient (ICC) for radiologic parameters and the Chertsey test.

RESULTS

The Chertsey test was positive in 13 (33.3%) of 39 ankle fractures. Patients with a positive Chertsey test showed a significant increase in syndesmotic width and volume compared with Chertsey - and control group. However, there was no significant difference between Chertsey - and the control group. All the ICC values were excellent for both radiologic measurements and test.

CONCLUSION

The Chertsey test is a reliable and useful test that can be used intraoperatively in the diagnosis of syndesmotic injuries.

LEVEL OF EVIDENCE

III, comparative series.

The effect of ankle distraction on arthroscopic evaluation of syndesmotic instability: A cadaveric study

BACKGROUND

To assist with visualization, orthopaedic surgeons often apply ankle distraction during arthroscopic procedures. The study aimed to investigate whether ankle distraction suppresses fibular motion in cadaveric specimens with an unstable syndesmotic injury.

METHODS

Fourteen fresh-frozen above knee specimens underwent arthroscopic assessment with 1) intact ligaments, 2) after sectioning of the anterior inferior tibiofibular ligament, the interosseous ligament, and the posterior inferior tibiofibular ligament, and 3) after sectioning of the deep and superficial deltoid ligament. In all scenarios, the lateral hook test, anterior-posterior hook test, and posterior-anterior hook test were applied. Each test was performed with and without ankle distraction. Coronal plane anterior and posterior tibiofibular diastasis as well as sagittal plane tibiofibular translation due to the applied load were arthroscopically measured.

FINDINGS

Tibiofibular diastasis in the coronal plane, as measured at both the anterior and posterior third of the incisura, was found to be significantly less when ankle distraction was applied, as compared to arthroscopic evaluation in the absence of distraction. In contrast, measurement of sagittal plane tibiofibular translation was not affected by ankle distraction.

INTERPRETATION

Since arthroscopic findings of syndesmotic instability are subtle the differential values of the syndesmotic measurements taken on and off distraction are clinically relevant. To optimally assess syndesmotic instability one should evaluate the syndesmosis without distraction or focus on fibular motion in the sagittal plane when distraction is required.

Effect of Sequential Sectioning of Ligaments on Syndesmotic Instability in the Coronal Plane Evaluated Arthroscopically

BACKGROUND

Arthroscopic evaluation of the syndesmosis allows direct visualization of syndesmotic instability. The purpose of this study was to determine the minimum degree of ligamentous injury necessary to destabilize the syndesmosis in the coronal plane when assessed arthroscopically and pinpoint where such instability should be measured within the incisura.

METHODS

Fourteen cadaveric specimens were divided into 2 groups and arthroscopically assessed first with the syndesmosis intact and then following serial differential ligamentous transection. Group 1 (n = 7): anterior-inferior tibiofibular (AITFL), interosseous (IOL), posterior-inferior tibiofibular (PITFL), and deltoid (DL) ligament. Group 2 (n = 7): PITFL-IOL-AITFL-DL. At each step, a standard 100-N lateral hook test was applied and tibiofibular coronal plane diastasis measured arthroscopically at both the anterior and posterior third of the incisura. These measurements were in turn compared with those of the stressed intact ligamentous state.

RESULTS

There was no significant syndesmotic instability measured at either the anterior or posterior margin of the incisura after transection of a singular ligament (AITFL or PITFL) or after the IOL was additionally transected. Diastasis at the posterior margin was significantly increased when all syndesmotic ligaments were sectioned (group 1: P = .018; group 2: P = .008), but this was not noted along the anterior margin. Diastasis at the anterior margin reached significance only with complete transection of syndesmosis and DL (group 1: P < .001; group 2: P = .044).

CONCLUSION

Under arthroscopic evaluation, the syndesmosis becomes unstable in the coronal plane only when all syndesmotic ligaments are transected, which should preferentially be measured at the posterior margin of the incisura. Anteriorly, diastasis becomes apparent only with addition of DL disruption, although this added finding may aid in diagnosis of occult deltoid injury.

CLINICAL RELEVANCE

AITFL, IOL, and PITFL need to be injured to produce coronal plane syndesmotic instability. Arthroscopic assessment of such instability should occur along the posterior margin of the incisura. When they exist, similar findings anteriorly suggest concomitant deltoid injury.

Arthroscopically measured syndesmotic stability after screw vs. suture button fixation in a cadaveric model

BACKGROUND

Appropriate management of ankle syndesmotic instability is needed to prevent the development of complications. Previous biomechanical studies have evaluated movement of the fibula after screw or suture button fixations with different results, most likely being caused by variations in experimental setups that did not mirror the in vivo clinical setting. This study aimed to arthroscopically compare in a cadaveric model the stability of syndesmotic fixation with either a suture button or syndesmotic screw.

METHODS

Eight fresh matched pairs of human ankle cadaver specimens (above knee) underwent arthroscopic assessment with (1) intact ligaments, (2) after complete disruption, and (3) after repair with either a quadracortical syndesmotic screw or suture button construct. In every stage, four loading conditions were considered under 100N of direct force: 1) unstressed, 2) lateral hook test, 3) anterior to posterior (AP) translation test, and 4) posterior to anterior (PA) translation test. Coronal plane tibiofibular diastasis, as well as sagittal plane tibiofibular translation, were arthroscopically measured.

RESULTS

Coronal plane anterior and posterior tibiofibular diastasis and sagittal plane tibiofibular translation were measured using probes of increasing diameters. Following screw fixation, syndesmotic stability was similar to the uninjured syndesmosis in the coronal plane (anterior, median 0.0mm [IQR 0.0-0.3] vs. 0.3mm [IQR 0.2-0.3]; p=0.57; posterior, median 0.1mm [IQR 0.0-0.4] vs. 0.2mm [IQR 0.1-0.3]; p=1.0) but more rigid in the sagittal plane (median 0.0mm [IQR 0.0-0.1] vs. 1.0mm [IQR 0.4-1.5]; p=0.012). Repairing the unstable syndesmosis with a suture button construct resulted in coronal plane stability similar to the uninjured syndesmosis (anterior, median 0.2mm [IQR 0.1-0.3] vs. 0.2mm [IQR 0.1-0.3]; p=0.48; posterior, median 0.2mm [IQR 0.1-0.3] vs. 0.3mm [IQR 0.1-0.5]; p=0.44). However, sagittal plane fibular motion remained unstable as compared to the uninjured syndesmosis (median 2.2mm [IQR 1.6-2.6] vs. 0.8mm [IQR 0.4-1.3]; p=0.012).

CONCLUSION

Current fixation methods for syndesmotic disruption maintain coronal plane fibular stability. Screw and suture button constructs, however, respectively resulted in greater or insufficient constraint to fibular motion in the sagittal plane as compared to the intact syndesmotic ligament. These findings suggest that neither traditional screw nor suture button fixations optimally stabilize the syndesmosis, which may have implications for postoperative care and clinical outcomes.

Management of syndesmotic injuries of the ankle

Injuries to the tibioperoneal syndesmosis are more frequent than previously thought and their treatment is essential for the stability of the ankle mortise.

Recognition of these lesions is essential to avoid long-term morbidity.

Diagnosis often requires complete history, physical examination, weight-bearing radiographs and MRI.

Treatment-oriented classification is mandatory.

It is recommended that acute stable injuries are treated conservatively and unstable injuries surgically by syndesmotic screw fixation, suture-button dynamic fixation or direct repair of the anterior inferior tibiofibular ligament.

Subacute injuries may require ligamentoplasty and chronic lesions are best treated by syndesmotic fusion.

However, knowledge about syndesmotic injuries is still limited as recommendations for surgical treatment are only based on level IV and V evidence.

Cite this article: EFORT Open Rev 2017;2:403–409. DOI: 10.1302/2058-5241.2.160084

Distal Tibiofibular Syndesmosis: Anatomy, Biomechanics, Injury and Management

A stable and precise articulation of the distal tibiofibular syndesmosis is essential for normal motion of the ankle joint. Injury to the syndesmosis occurs through rupture or bony avulsion of the syndesmotic ligament complex. External rotation of the talus has been identified as the major mechanism of syndesmotic injury. None of the syndesmotic stress tests was sensitive or specific; therefore the diagnosis of syndesmotic injury should not be made based on the medical history and physical examination alone. With the improvement in ankle arthroscopic technique, it can be used as a diagnostic and therapeutic tool in the management of distal tibiofibular syndesmosis injury.

Overtightening of the syndesmosis revisited and the effect of syndesmotic malreduction on ankle dorsiflexion

BACKGROUND

Ankle syndesmotic injuries are a significant source of morbidity and require anatomic reduction to optimize outcomes. Although a previous study concluded that maximal dorsiflexion during syndesmotic fixation was not required, methodologic weaknesses existed and several studies have demonstrated improved ankle dorsiflexion after removal of syndesmotic screws. The purposes of the current investigation are: (1) To assess the effect of compressive syndesmotic screw fixation on ankle dorsiflexion utilizing a controlled load and instrumentation allowing for precise measurement of motion. (2) To assess the effect of anterior & posterior syndesmotic malreduction after compressive syndesmotic screw fixation on ankle dorsiflexion.

MATERIAL AND METHODS

Fifteen lower limb cadaveric leg specimens were utilized for the study. Ankle dorsiflexion was measured utilizing a precise micro-sensor system after application of a consistent load in the (1) intact state, (2) after compression fixation with a syndesmotic screw and (3) after anterior & (4) posterior malreduction of the syndesmosis.

RESULTS

Following screw compression of the nondisplaced syndesmosis, dorsiflexion ROM was 99.7±0.87% (mean±standard error) of baseline ankle ROM. Anterior and posterior malreduction of the syndesmosis resulted in dorsiflexion ROM that was 99.1±1.75% and 98.6±1.56% of baseline ankle ROM, respectively. One-way ANOVA was performed showing no statistical significance between groups (p-value=0.88). Two-way ANOVA comparing the groups with respect to both the reduction condition (intact, anatomic reduction, anterior displacement, posterior displacement) and the displacement order (anterior first, posterior first) did not demonstrate a statistically significant effect (p-value=0.99).

CONCLUSION

Maximal dorsiflexion of the ankle is not required prior to syndesmotic fixation as no loss of motion was seen with compressive fixation in our cadaver model. Anterior or posterior syndesmotic malreduction following syndesmotic screw fixation had no effect on ankle dorsiflexion. Poor patient outcomes after syndesmotic malreduction may be due to other factors and not loss of dorsiflexion motion.

LEVEL OF EVIDENCE

IV.

Arthroscopic Correlates of Subtle Syndesmotic Injury

BACKGROUND

Arthroscopic criteria for identifying syndesmotic disruption have been variable and subjective. We aimed to quantify syndesmotic disruption arthroscopically using a standardized measurement device.

METHODS

Ten cadaveric lower extremity specimens were tested in intact state and after serial sectioning of the syndesmotic structures (anterior inferior tibiofibular ligament [AiTFL], interosseous ligament [IOL], posterior inferior tibiofibular ligament [PiTFL], deltoid). Diagnostic ankle arthroscopy was performed after each sectioning. Manual external rotational stress was applied across the tibiofibular joint. Custom-manufactured spherical balls of increasing diameter mounted on the end of an arthroscopic probe were inserted into the tibiofibular space to determine the degree of diastasis of the tibiofibular joint under each condition.

RESULTS

A ball 3 mm in diameter reliably indicated a high likelihood of combined disruption of the AiTFL and IOL. Disruption of the AiTFL alone could not be reliably distinguished from the intact state.

CONCLUSION

Use of a spherical probe placed into the tibiofibular space during manual external rotation of the ankle provided an objective measure of syndesmotic instability. Passage of a 2.5-mm probe indicated some disruption of the syndesmosis, but the test had poor negative predictive value. Passage of a 3.0-mm spherical probe indicated very high likelihood of disruption of both the AiTFL and the IOL.

CLINICAL RELEVANCE

The findings challenge the previously used but unsupported standard of a 2-mm diastasis of the tibiofibular articulation for diagnosis of subtle syndesmotic instability.

Management of acute injuries of the tibiofibular syndesmosis

The syndesmosis is important for ankle stability and load transmission and is commonly injured in association with ankle sprains and fractures. Syndesmotic disruption is associated with between 5 and 10% of ankle sprains and 11-20% of operative ankle fractures. Failure to recognize and appropriately treat syndesmotic disruption can portend poor functional outcomes for patients; therefore, early recognition and appropriate treatment are critical. Syndesmotic injuries are difficult to diagnose, and even when identified and treated, a slightly malreduced syndesmosis can lead to joint destruction and poor functional outcomes. This review will discuss the relevant anatomy, biomechanics, mechanism of injury, clinical evaluation, and treatment of acute injuries to the ankle syndesmosis.

Isolated Syndesmosis Diastasis: Computed Tomography Scan Assessment With Arthroscopic Correlation

PURPOSE

To investigate which method can predict tibiofibular diastasis more accurately among the tibiofibular interval at the ankle joint level or previous parameters taken 1 cm above the joint line.

METHODS

An arthroscopic examination was performed in 78 consecutive patients with anterolateral ankle pain. Four different methods were performed to take measurements of the tibiofibular interval using an axial computed tomography (CT) scan under existing arthroscopic diagnosis. Three previously reported parameters were assessed at 1 cm above the joint level. In the first method, 2 measurements were obtained. The anterior measurement was the closest distance between the anterior border of the fibula and anterior tibial tubercle. The posterior measurement was the closest distance between the medial border of the fibula and posterior tibial tubercle. In the second method, an angle between the fibular axis and the line connecting the anterior and posterior tibial tubercle was measured. In the third method, the nearest distance between the line perpendicular to the line connecting the tubercles at the anterior tubercle of the distal tibia and the anterior-most margin of the fibula was measured. The fourth method, which was developed in this study, measured the narrowest tibiofibular distance at the joint level. Data were analyzed using Student's t-test and the receiver operating characteristic curve to make comparisons among 4 CT-based parameters.

RESULTS

In the comparison between the patients with arthroscopic diastasis and without diastasis, the posterior parameter in the first method and the narrowest tibiofibular distance at the joint level in the fourth method showed a significant difference (P < .05) The areas under the receiver operating characteristic curve (AUCs) of the anterior and posterior parameter of the first method were 0.58 (95% confidence interval [CI], 0.43-0.73; P = .167) of anterior measurement and 0.6 (95% CI, 0.45-0.75; P = .029) of posterior measurement, respectively. The second and third methods presented AUCs of 0.59 (95% CI, 0.44-0.74; P = .458) and 0.48 (95% CI, 0.33-0.64; P = .987), respectively. The fourth method presented an AUC of 0.86 (95% CI, 0.75-0.94; P = .000). When the syndesmosis was measured at the joint level, 2 mm of syndesmosis interval as a cutoff value showed 76% of sensitivity and 81% of specificity.

CONCLUSIONS

Syndesmosis assessment using an axial CT scan at the joint level best correlated with the arthroscopic examination. When there is more than 2 mm of widening in syndesmosis on the axial CT scan at the joint level, there is a high likelihood of diastasis of the distal tibiofibular syndesmosis in patients who are suspicious clinically to have acute or chronic syndesmosis lesion.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Arthroscopic Quantification of Syndesmotic Instability in a Cadaveric Model

PURPOSE

To investigate whether arthroscopy or stress radiography can identify instability resulting from single-ligament injury of the ankle syndesmosis and to determine whether either modality is capable of differentiating between various levels of ligament injury.

METHODS

Syndesmotic/deltoid ligament sectioning was performed in 10 cadaver legs. Arthroscopic evaluation and fluoroscopic stress testing were completed after each sectioning. In group 1 (n = 5), sectioning began with anteroinferior tibiofibular ligament (AITFL), then interosseous membrane (IOM), posteroinferior tibiofibular ligament (PITFL), and deltoid. In group 2 (n = 5), this order was reversed. Measurements were made by determining the largest-sized probe that would fit in the anterior and posterior syndesmosis. Radiographic parameters included tibiofibular overlap/clear space and medial clear space.

RESULTS

No radiographic measurement proved useful in distinguishing between intact and transected AITFL. Anterior probe (AP) size reached significance when distinguishing between intact and AITFL-transected specimens (P < .0001). AP detected significant differences comparing single with 2-, 3-, and 4-ligament (AITFL, IOM, PITFL, deltoid) disruptions (P = .05, <.0001, and <.0001, respectively). Significant differences were observed between 2- and 3/4-ligament (P = .02) transections. Posterior probe (PP) size detected significant differences between intact and single-, double-, triple-, and complete ligament transections (P values .0006, <.0001, <.0001, <.001, respectively). PP detected significant differences between single- and double-, triple-, and complete ligament transection models (P = .0075, .0010, and .0010, respectively). PP distinguished between 2- and 3/4-ligament (P = .03) transections.

CONCLUSIONS

Stress radiography did not distinguish between intact and single-ligament disruption, and was unreliable in distinguishing between sequential transection models. Arthroscopy significantly predicted isolated disruption of the AITFL or deltoid ligaments. Also, probing was able to differentiate between most patterns of ligament injury, including sequential transections.

CLINICAL RELEVANCE

These data can aid surgeons during arthroscopy of the ankle when attempting to correlate intraoperative syndesmotic evaluation findings with the extent of ligament injury.

Arthroscopic Evaluation of Syndesmotic Instability and Malreduction

Ankle fractures are a common injury treated by orthopaedic surgeons. The distal tibiofibular syndesmosis can be injured during these fractures as well as in isolation. They pose a significant challenge with regard to the diagnosis of instability as well as evaluating reduction after fixation. Multiple studies have demonstrated that traditional radiographic analysis fails to accurately identify syndesmotic diastasis, instability, or malreduction. Ankle arthroscopy has been proposed as an alternative way to evaluate the syndesmosis. Ten transtibial amputation cadavers were utilized for this study. Two distinct analyses were undertaken. The first, analysis of instability, utilized 2 dissection groups, a superficial dissection only and a partial disruption instability model. The second analysis was of syndesmotic malreduction. For this, all 10 specimens underwent complete disruption of the syndesmosis and subsequent fixation in either anatomic alignment or malreduction. Both analyses were performed by surgeons blinded to the condition of the syndesmosis. Two groups of surgeons were able to identify syndesmotic instability a combined 75% of the time. Malreduction diagnosis was mixed with a 100% accurate diagnosis of sagittal plane displacement but only 50% accuracy for rotation and 17% for an anatomic reduction. Syndesmotic injury during ankle fracture presents a significant problem to the treating surgeon. Ankle arthroscopy has been shown in the literature to be highly sensitive for diagnosing instability but has not been evaluated in diagnosing malreduction. The current study shows moderate success in diagnosing both malreduction and instability.

LEVELS OF EVIDENCE

Therapeutic, Level V: Basic Science.